In recent years, a touch detection device capable of detecting an external proximity object referred to as a so-called touch panel has attracted attention. The touch panel has been used as a display device with a touch detection function which is mounted on or integrated with a display device such as a liquid crystal display device. In this display device with a touch detection function, various button images or the like are displayed on the display device, and the information can be input by the touch panel instead of normal mechanical buttons. Since such a display device with a touch detection function having a touch panel does not need to have an input device such as a keyboard, a mouse or a keypad, its use tends to increase with the inclusion of mobile information terminals such as mobile phones in addition to computers.
As a type of a touch detection device, some types such as an optical type, a resistance type and an electrostatic capacitance type have been known. Among these types, an electrostatic capacitance type touch detection device has a relatively simple structure and consumes less power and so is used for mobile information terminals and the like. For example, Japanese Patent Application Laid-Open Publication No. 2014-160458 (Patent Document 1) describes an electrostatic capacitance type touch panel.